1. Field of the Invention
The present invention relates to electronic devices, and more particularly, to an electronic device for use in a communication apparatus or the like using a microwave or millimeter wave band.
2. Description of the Related Art
FIG. 3 shows an example of a conventional electronic device for use in a microwave or millimeter wave band. The electronic device 200 includes functional blocks: an oscillator module 201, a resonator 202, a multiplier module 203, a filter module 204, a mixer module 205 and an amplifier module 206, which are encapsulated in a package, and which are mounted on a base member 207 to be connected to an external circuit. Such a structure is called a discrete MIC (microwave integrated circuit).
FIG. 4 shows another example of a conventional electronic device. The electronic device 300 is formed by integrating most of the functional blocks into one integrated circuit (IC). In other words, on a GaAs base-member 301 are formed an oscillator 302, a multiplier 303, a filter 304, a mixer 305, and an amplifier 306. Such a structure is called an MMIC (monolithic MIC). Since no portion corresponding to the resonator 202 included in the structure in FIG. 3 is formed on the GaAs IC, it is not completely integrated.
In the discrete-MIC-structure electronic device, each functional block is packaged, and the packaged blocks are arranged to form one electronic device. This makes it impossible to reduce the size of the electronic device.
In the MMIC-structure electronic device, an advantageous size reduction can be obtained. However, the IC is fundamentally designed to meet a particular requirement, which limits the amount of production, and increases production costs and the degree of integration. Thus, the yield per wafer deteriorates disadvantageously. In addition, since the resonator cannot be integrated into the conventional example in FIG. 4, there are some functions which cannot be performed by the integrated MMIC. In this case the resonator is externally mounted, which undercuts the merits of any size reduction that may be obtained.